Metformin in pregnancy shows no safety concerns, study reveals

A large study has shown no safety issues of concern relating to the use of metformin during pregnancy. The MHRA has notified that the licence for metformin can be considered for use during pregnancy and the periconceptional phase as an addition or an alternative to insulin, if clinically needed.

National guidelines (from NICE and SIGN) in the UK already recommend metformin for use in diabetes during pregnancy and gestational diabetes if a healthcare professional feels it is appropriate.

Following a European review of data from a non-interventional cohort study of population registries in Finland (the CLUE study), the product information for metformin is being updated to permit the use of metformin during pregnancy and the periconceptional phase as an addition or an alternative to insulin, if clinically needed.

The Medicines for Women’s Health Expert Advisory Group of the Commission on Human Medicines has also reviewed the data from the study and agreed that the product information should be updated.

The study investigated immediate and longer-term effects of exposure to metformin in-utero on children born to patients with pre-existing type 2 diabetes, gestational diabetes, or polycystic ovary syndrome. The results of the study were reassuring, with no safety signals of concern identified for use of metformin in pregnancy relating either to those who were pregnant or their baby.

Among secondary outcomes, similar rates of births that were small (low weight) for gestational age were observed with exposure to metformin and within the group of patients with untreated gestational diabetes. By contrast, an increased risk of small for gestational age was observed with exposure to metformin compared with insulin, which may relate to an overall increase in body weight due to use of insulin.